[Source - Wiki] Vālmīki was going to the river Ganges for his daily ablutions. A disciple by the name Bharadvāja was carrying his clothes. On the way, they came across the Tamasa Stream. Looking at the stream, Vālmīki said to his disciple, "Look, how clear is this water, like the mind of a good man! I will bathe here today." When he was looking for a suitable place to step into the stream, he saw a crane couple mating. Vālmīki felt very pleased on seeing the happy birds. Suddenly, hit by an arrow, the male bird died on the spot. Filled by sorrow, its mate screamed in agony and died of shock. Vālmīki's heart melted at this pitiful sight. He looked around to find out who had shot the bird. He saw a hunter with a bow and arrows, nearby. Vālmīki became very angry. His lips opened and he cried out,
mā niṣāda pratiṣṭhāṁ tvamagamaḥ śāśvatīḥ samāḥ
yat krauńcamithunādekam avadhīḥ kāmamohitam
You will find no rest for the long years of Eternity
For you killed a bird in love and unsuspecting.